Due to frequent problems with existing appliances and a problem that prevented us from upgrading to new AsyncOS releases we had to replace our physical appliances. The swap had to be done with no downtime/outage.

I have searched the web and there are lots of things to try if you have just migrated to server 2003 (which we havent)

There is lots of information relating to the Offline address book also, stating to check there is replication server specfied for each of the folders, however I have checked and everything seems to be in place.